try:
    print('开始try')
    a=100/0
    print('result',a)
except ValueError as e:
    print('ValueError',e)
except ZeroDivisionError as e:
    print('ZeroDivisionError', e)
    # raise 把错误上抛到上一层
else:
    print('unknow error!')
finally:
    print('不好意思')

# 调用栈

